U.S. Pat. No. 5,948,343 discloses a hollow body and a method for manufacturing the hollow body, in which a sphere is pushed through the injection mold as a displacement body. The sphere is held in the injection mold during the filling of the melt into the injection mold and exits at the opposite end of the plastic body into a secondary cavity together with the displaced melt. As a result, the plastic body has large openings, the diameter of which corresponds to the inner diameter of the plastic body, at its ends.
It is also known to leave the displacement body in the plastic body so that a large outlet opening can be avoided.